Endless-track vehicle



Jan. 30, 19.23. 1,443,871

L. K. DAVIS. ENDLESSIRACK VEHICLE.

F||.EDIMAY 10, 1922. 6 sHEETs-sHEET 1 I lll M @nua/wkn ewwaw Jan. 30, 1923.

L. K. DAVIS, ENDLEss TRACK Vai-n cLE. Fl LED lvAY 10 1922 Jan. 3o, 1923.

Lr K. DAVIS. ENDLEss TRACK VEHIcuE. FILED MAY 10, 1922.

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L. K. DAVIS. ENDLEss TRACK VEHlcLE.

F|LED MAY 10.

Patented Jan. 30, 1923.

UNiTED STATES, PATEN f.

LEWIS K. DAVIS, OIE WASHINGTON, DISTRICT OF COLUMBIA.

I ENDLESS-TRACK VEHICLE.

Application filed May 10, 1922. Serial No. 559,857.

T NZZ /iciomit may cam-cru tle and where iubber or fiber tracks are used Be it known that I, Lewis li. Davis, atlie surface quickly wears out. rl`hird` the citizen of the Vnited States, residing at track is often thrown off of the supporting Washington` in the District of Columbia. wheels while it is braked, since the turning have invented certain new and useful lmaction tends to wrench the track free tliere- 60 provements in. Endless-T rack Vehicles, of from. 'l`hus time is lost in repair and the which the following is a'specitication. utility of track-laying vehicles is greatly My invention relates to track-laying ve diminished. These are some. of the disadliicles, and particularly to the steering vantages of the present system of steering y l0 mechanism of such vehicles. track-laying vehicles. 65

An object of my invention is to permit the My invention comprises a vehicle; which is iexible tracks upon which the vehicle runs adapted to run on self-laying tracks, 0r to be warped at the same time that the upon wheels on the road. There zare two brake is applied to one of them` so that the sets of steering mechanisms, one of which is turning ot' the vehicle can be easily and adapted to be used when the vehicle is run- 70 quickly effected. ning on wheels` the other when ruiming on Another object of my invention is'to prothe tracks. The steering mechanism usedV vide a vehicle that can run on wheels or on. when the vehicle rims on wheels gives a a self-laid track, and in which steering is acquick motion to the guide or steering wheels comp-lished by means of guide wheels that. and these. wheels may be turned through a 75 are designed to turn less quickly when the wide angle such as is customary in autoveliicle is running on tracks than when runmobiles. T he steering of the. vehicle, when ning on wheels. l running on the tracks is effected by means A still further object ot' my linvention is of warping the tracks or bending them latto provide a mechanism for moving the erally and at the same time applying the 80 guide wheels of a vehicle ada ted to iun brake to one of them. The warping of the either on wheels or on a sel -laid track. tracks isin a direction to aid in the turning wherein the angie of turning of the guide of the vehicle. For purpose of warping the wheels may be greater when the vehicle isv tracks, the guide wheels are caused to turn,

running on wheels. which throws the tracks out of a straight 85 A further object of the invention is to so line. ln this latter case, the speed with support the vehicle on the tracks that when which they turn is less than when the vethe tracks are warped or bent laterally durhicle runs on wheels, and, moreover. the ing'the steering operation the supports may angle through which the steering wheels be moved laterally with the tracks, provimay turn is also less. The bogies for sup- 90 sion-being also made for returning the supporting the load-bearing wheels are so ports to normal position when the steering mounted that they may slide laterally, so mechanism is operated to guide the vehicle that when the tracks are warped the bogies straight ahead. i may be carried with the track. employ a 40 Heretofore. in order to turn track-laying type of flexible track permitting lateral 95 vehicles, it has been necessary to brake one AHerring which I have found to be particuof the tracks to either partially or totally larly adapted for use in this type of vehicle. stop that track. The braked track will act Vith these and vother objects in view as a pivot, and the moving track to which which may be incident to my improvements,

the power is being applied will cause the the invention consists in the parts and com- 100 vehicle to turn about the braked track as a binations to be hereinafter set forth and pivot. Such turning has notable disadvanclaimed, with the understanding that the tages. several 'necessary elements comprising my First, the braked track digs deeply into invention may be varied in construction,

the soil of the road. thereby harming its proportions and arrangement, without de- 105 surface. Second. the track that is braked is parting from the spirit and scope ot' the apquickly worn out hy reason ot the tremenpended claims.

dous grinding actionto which it is subjected In order. to make my invention more in turning. This grinding causes the metal clearly understood` I have shwn in the acof the tracks to become crystallized and britconipanying drawings means for carrying 110 the same into practical effect, without limiting the improvements in their useful applications to the particular constructions, which for the purpose of explanation, have been made the subject of illustration.

In the drawings Figure 1 is a top plan view showing the application of my mechanism to a track-laying vehicle;

Fig. 2 is a view in side elevation of the structure shown in Fig. 1;

Fig. 3 is a. diagrammatic illustration showing the angle of deflection of the steering wheels where the -vehicle is running 4on wheels; l

Fig. 4 is a diagrammatic illustration show.- ing the angle of deflection of the steering wheels where the vehicle is running on .selflaid tracks;

Fig. 5 is a longitudinal section through the center of the steering gear housing;

Fig. 6 is a detail view of the steering gear housing, the steering rod and links; i

Fig. 7 is a cross-sectional view on line 7 7 of Fig. 5;

Fig. 8 is a detail view partly in section of p the steering and braking mechanism, showing the clutching mechanism which cooperates therewith;

Fig. 9 is a detail view partly in section of the brake rod gear and housing;

Fig. 10 is a detail view of a form of bogy and support which I may employ in my mechanism;

Fig. 411 is another detail view partly in section, of the form of bogy shown in Fig. 10;

Fig. 12 is a topplan view of one type of track which I'employ;

Fig. 13 is a view in longitudinal'section on the line 13-13 of Fig. 12;

Fig. 14 is an end view of thetrack shown in Fig. 12; A

Fig. 15 is a detail view of another form of bogy;

Fig. 16 is a view partly in section of the structure shown in Fig. 15, illustrating the mounting of the bogy on cross-bars;

Fig. 17 is a view partly in section showing the application of still another type of bogy;

Referring to the drawings, Figs. 1 to 4 inclusive, I have shown a track-laying vehicle having a frame 1. and drive-wheels 2. which are connected through a differential 3 to a suitable source of power (not shown) carried on the vehicle. For the purpose of steering the vehicle Ihave shown guide wheels 4 on stub axles pivoted on pivots 5 on a front axle 6. Connected to the guide wheels -4 are levers 7 which are pivoted at 8 toa connecting rod 9. To one of the levers 7 1s connected a, lever 11, preferably formed integrally therewith, and constituting with said lever 7 a bell-crank lever. To the free end of the lever l1 is pivoted at 12, a steering' rod 13, which is adapted to be pushed in a forward or pulled in a backward direction, as later described, to turn the guide wheels 4.

Adapted to lit over the drive wheels 2 and the guide wheels 4 are fibre or rubber tracks 14 having their ends bolted together at 15 to enable the tracks to be readily applied to or demounted from the vehicle. To hold the tracks taut and at the same time to allow them to give to a heavy jolt, I have provided lever arms 16, pivoted at points 17 on supports 18, attached to the vehicle frame 1. At one end of the lever arms 16 are mounted rollers 19 which bear against the tracks 14 and exert pressure thereon by reason of springs 21 attached to the other ends of the levers 16 and to the frame 1 of the vehicle body.

tracks 14. At their upper end the platesl 23 o'f each bogy 22 are formed with a sleeve 26 through which passes a crosshar 27. The sleeves 26 are provided at their ends with caps 28 which are screwthreaded thereon and form with the sleeves 26, ball-races for balls 29. These ball-bearing supports permit the bogies 22 to easily swing on the crossbars 27 as pivots, or to Slide laterally thereon.

To hold the bogies 22 in proper position. I have provided the crossbars 27 with annular shoulder members or collars 31 which are adapted to be held in tight and non-v slipping engagement with the crossbars 27 by means of tightening screws 32. The annular shoulder members 31 are placed on either side of the sleeves 26 of the bogies 22, and between the caps 28 and the shoulder members 31 I have mounted compression springs 33 which allow the bogies to slide laterally on the crossbars 27, but tend,f al ways to return them to their normal position.

Clamped to the crossbars 27 are. clamping members 34 each comprising a lower half 35 and an upper half 36. which are held together by bolts 37. each clamping member 34 is preferably in tegra-lly formed with a plunger 38 having a shoulder 39 at its vlower extremity. The plunger 38 lits within an annular housing 40 carried on a support 41 that is bolted by means of bolts 42 to the frame 1 of the vehicle. Each housing 40 is provided on either side with a slot 43 in which is adapted to slide a plug 44 which passes through the plunger 38. Compressed between the The upper half 36 of to the tracks 14. lVhen the vehicle is travelwhen the tracks are mounted on the ve-V hicle. This condition is diagrammatically `illustrated in Figs. 3 and 4, in which Fig. 3

shows the turning of the guide wheels when the track is removed, and Fig. 4 shows the turning of the guide wheels when the track is on the vehicle. The degrees of turning shown are merely illustrative and the angles given have no significance. `When the track is on the vehicle the turning of the guide wheels warps the track or bends it laterally1 which aids in turning the vehicle, as will be later described.

To steer the vehicle, I have shown a steering wheel 46 formed with spider arms 47, which at their point of juncture are formed with a hexagonal aperture 48 (see Figs. 5 and 7). have shown two steering columns 49 and 51. The steering column 49 is adapt ed to rotate within the steering column 51 and extends beyond the upper extremity of the steering column 51. The steering co1- umn 49 is provided with a key-way 52, and surrounding the portion of the steering column 49 having the key-way therein, is aY hexagonal shoulder 53, having a key-way 54 therein. The key 55 is adapted to fit in the key-way 52 of-the steering column 49, and the key-way 54 of the hexagonal shoulder 53. The key 55 tightly and immovably holds the hexagonal shoulder 53 to the steering -column 49.

Adapted to pass through the juncture of the spider arms 47 are screws 56 which screw into apertures 57 of the hexagonal collar 53. As shown in Figs. 5 and 7, the screws 56, when tightly screwed into the apertures 57 of the hexagonal Shoulder 53 hold the steering wheel 46 in tight engagement with the steering column 49, and the steering column 49 may be rotated to steer the vehicle.

By loosening the screws 56. the steering column 46 may be slipped down over a hexagonal portion 5S of the steering column 5l, and the screws 56 again screwed into apertures 59 in suchV hexagonal portion, whereupon the steering wheel 46 may be made to turn thesteering column 51 without turning the steering column 49.

Adapted to extend from one side to the other of the Vframe 1, is asupport 61 which is firmly bolted at leither end to the support 1l on either side of the vehicle. Bolted by means of bolt 62 to the lower side of the support 61, is a gear casingsupport arm 63 formed integrally with a gear casing 64. The steering columns 49 and 51 pass through a gear casing top 65 'which is screw-threaded into the gear casing.

Within the gear casing, mounted on the steering column 51, is a worm 66, and upon the steering A'column 49 on the portion of the column that extends through the worm 66, is a worm 67.

The lower end of the steering column 49 is journalled in a beaiing`68 formed in the bottom of the gear casing 64, and the lower end of the column 49 is reduced at 69. forming a shoulder 70 that prevents the steering column 49 from sliding in a downward direction. A retaining nut 71 prevents the steering column 49 from sliding in an upward direction. Journalled in the gear casing 64 is a shaft 72 to which is keyed by means of a key 73, a worm sector 74 that meshes with the worm 66. Journalled in the lower part of the gear casing 64 is a shaft 75 which is keyed by means of a key 76 to a worm sector 78 that meshes with the worm` 67. The worm 66 is of a greater pitch than the worm 67 and, therefore, for a corresponding degree of turn of the respectively steering columns attached to these worms, there would be a larger angular movement of the shaft 72 than there wouldbe of the shaft 75. Fastened to the gear casing 64 by means of screws 79is a side plate-S1. The worm sector 74 is so formed that it may have a greater angular movement before it encounters and is arrested by the side plate 81, than is the case with the worm sector 76,-which latter is larger in, size and is. therefore, more limited in movement.

In order to permit either one of the two shafts 72 or 75 to operate the steering mecha` nism. I have mounted on the shaft '72 a the shaft 72 and is prevented from slipping from off the end-thereof by means of a lock nut 83. integrally formedA .with the clutch member 82 isa. link 84 that is pivoted at its end 85 in a slot 86 formed inthe enlarged end 87 of the steering rod 13. The link 84 is formed with a slot 88 in which is adapted to clutch member 82 which is free to rotate on slide a lug 89 carried on a link 0l. The link Ell integrally formed with a clutch member 02 which is adapted to freely rotate on the shat't T5 and is held from slipping oti' the end thereotl by means ot a lock nut 93.

Pivoted at 94. on a support piece 95. attached to the gear casing 64. is a clutch arm 96 carrying upper lugs 9T and lower lugs 98. The upperlugs 97 fit within a groove 99 formed in a clutch member 101 that is keyed to rotate with shaft T2 but adapted to sli-de thereon so that when the clutch lever 96 is moved in a counter clock-wise direction, the clutch member 101 engages with the clutch member 82. lllhen the clutch lever is thrown in a position to engage the clutch member 82 with theclutch member 101, the lugs 98 engage a groove 100 in a clutch member 102 that is keyed to rotate with shaft 75 and adapted to slide thereon, to throw clutch member 102 out of engagement with the clutch member 92. By means of moving the clutch lever 96 in either one direction or the other, either of the gear sectors 74 or 78 may be thrown into engagement with the steering mechanism to operate the same.

The clutch lever 96 will be moved in either one direction or the other, depending u pon which of the steering columns is used. It the vehicle is running on tracks and the steering column 49 is being utilized, the clutch lever will be thrown, as indicated in Fig. 8, whereby clutch members 92 and 102 are brought into engagement, and clutch members 82 and 101 are thrown out of engagement. This will insure that the guide wheels will turn more slowly and through a more limited angle than is the case where the clutch lever is thrown to cause clutch member 82 and clutch member 101 to engage.

One end of the shaft 7 5 is journalled in a gear casing 103, preferably formed with a support arm 104, that is firmly bolted by means of a bolt 105 to the support 61. The gear casing-103 is formed with a bearing 106 through which the end of the s haft 7 5 projects, permitting tree rotation of the shaft. Keyed to the shaft 7 5 and mounted within the casing 103 is ak sector' of a beveled gear 10T which meshes with another sector of a beveled gear 108` which latter is mounted on a bolt 109 that extends through the casing 108 and is held in position by means ot a nut 111. The gear 108 is preterably formed integrally with a brake-lever 112- in the casing. whereby the break-lever 112 has tree lateral movement. A casing cover 114 Jforms a complete housing for the gears and is bolted by mea-iis ot bolts 115 to the casing. The casing cover 114 is formed with a bearing 116 therein in which the shaft 'l' 5 is adapted to rotate. There is which extends through a slot 113 formed in the casing cover a slot 11T through which the brake-lever 112 may hav(` tree lateral movement.

Lateral movement ot the brake-lever 11;)- is adapted to operate a mechanism to apply brakes to either one ot the two drive wheels. rl`he drive wheel lying on the inside of the arc ot turning is braked in making a turn. The braking ot the drive wheel aids the warping of the track in turning the vehicle and takes place at the same time, as

will be later explained.. Attached to the` ends ot` the brake-lever 112 and pivotally connected thereto. are brake rods 118 formed with bit'urc-.ited ends 119 through which are adapted to pass bolt-s 121 held in place by means ot nuts 122. i

The movement of the brake-lever 112 is transmitted to the brake-rods- 118, to levers 123, to hollow shafts 124 rotatably mounted on the vehicle, from whence motion is transmitted to levers 125- and trom thence through rods 126 to the braking mechanism.

The braking mechanism is so adjusted that upon movement of the brake-lever 112 in either direction the brake on one side only of the vehicle will be applied. This braking takes place on the side ot the vehicle in which the brake-rod 118 is moved in a 'torward direction,

Should it be necessary to apply the brake to both rear wheels at once` as when stoppingl the vehicle, 1 have provided a mechanism which comprises a foot-brake pedal 127 pivoted on a support 128, to which is pivotally attached a brake-rod 129. The brakerod 129 transmits motion to a lever 131 and from thence to a shaft 132 journalled within the hollow shaft 124. Rotation ot the shaft 132 moves levers 133 to pull forward rods 134 and apply the brakes to both drive wheels at the same time.

It is obvious that rods 134 and 126 must lead to two different brake bands, since thev are operated independently. This has not been illustrated in detail since the specific character ot the brake 4bands or other mechanism operated by the rods 134 and 126 clutch handle 96 is moved so that the clutch member 101 engages member 82` and then motion ot steering wheel 46 will be transmitted through the steering column 51` the worm 66, worm sector T4, and through the shaft 7 2 and link 84 to the steering rod 13. The speed with which the guide wheels mayvl be turned is similar' to that of other wheel-'supported automotive vehicles of the 4same class, and the maximum angularmovement of the guide wheels likewise correj n 5 sponds to the usual practice.

There can be no braking of either of the drive wheels separately, but should it become done through the foot-lever 127.

'V 0 lVhere the country is rough or the roads muddy, and the driver ,desires to use the vehicle as a track-laying vehicle, the bogies 22 are put in place and the tracks 14 mounted on the vehicle, as illustrated in F ig. 2.

' 5 The clutch handle 96 is positioned, asvillustrated inFig. 8, wherein clutch member 82 and clutch member 101 are not in engagement, but clutch member 92 and clutch member 102 are locked.v The steering wheel is placed on steering column 49 and the movement of the steering wheel will operate worm 67 and move worm` sector 78 to rotate shaft 75. As before mentioned, the speed with which shaft may be rotated is lless than is the case with the shaft 72, and likewise the degree limited, see Figs. 3 and 4.

A rotation of the steering wheel 46 will cause link 91 to transmit motion to the steering' rod 13. The rotation of the 'shaft 75 likewise, through gears 107 and 108, moves the brake-lever 112. The movement of the guide wheels 4, elfected by the movement of warp, tending to turn the vehicle in the direction of the warping. The flexible mounting of the bogies on the crossbars 27 permits the track to flex, but the springs 33 tend to vreturn the track tonormal position after the yguide wheels have assumed the straight ahead position. At the same time that the I'iexing of the track takes place, the brake-lever 112 is moved toapply the brake to the drive wheel on the inside of the turn. The combination of the warping of the tracks with the expedient of braking causes the vehicle to turn quickly without tearing the road surface or injuring the track itself. Other forms of apparatus may be used for the mounting of the supporting bogies on my vehicle. v

Should the use of a flexible liber or rubber track be inadvisable by reason of the character of the country to be crossed and of the type of roads encountered. I may utilize (see Figs. 12, 13 and 14) a track structure comprising metallic tra-ck plates 150, having at their bottom, spacer strips 151. rI`he spacer strips slightly raise the track structure above the ground and permit of the free play of a universal joint connecting structure 152, comprising a ball 153 and a socket 154 formed by means of joining two shoulders 155 and 156, by means of rivets or bolts 157. The ball 153 is fastened to a necessary to apply the brake. this may oe of rotation is more the steering rod 13, causes the tra-ck 14 tol vplished by 75 a construction in Figs. 15 and 16 which Acomprises supports 170 bolted to the frame 1 of the vehicle by means of bolts 171. The crossbars 27 have mounted thereonsleeves 172 which, with caps 173, form race-ways' 80 for balls 17 4, permitting the collars to either slide or to rotate freely onv the crossbars 27. The sleeves 172 are prevented from slidingoffof the-crossbars 27 by means of shoulders 175 which are dctachab'ly 'fastened to the crossbars 27. Bolted to the collar'172 are leaf-springs 176 each of which at the bottoms is bolted to a bogy 177 comprising side plates 17 8 in which is journaled the axle- 24 of a wheel 25. 'Thisconstruction `permits the. shock and jar to befabsorbed before it is transmitted to the ycrossbars 27, and moreover, permits the bogiesto readily accommodate themselves to the variouspositions of the track whenencountering` obstacles or when the track is warped in steering the vehicle.

In Fig. 17 I have shown a structure in Awhich -I have mounted bogies 181 on the crossbars 27 in the, manner indicated in F igs. 10 and 11. The bogies in the construction illustrated in F ig. 17 are, formed with spring compartments 182 in .which are placed compression springs 183 that absorb the shock transmitted from the axles 24 of 105 the wheels 25. Tie crossbars 27 are ycarried on longitudinal supports 184, there being a support on each side of the vehicle. These longitudinal supports are attached at their ends to leaf-springs 185 that support the 110 frame 1 of the vehicle. l I have devised a construction by which steering of a track-layingvehicle is accommeans of warping the track to effect the turn. shown "incombination withva construction which vautomatically brakes one of the tracks to aid vin turning the'vehicle when the tra-ck is warped.l The construction of track and of bogy supports for use with my mechanism insure proper operation of the deviceunder all conditions of use. A

'lVhile I have shown and described the preferred embodiment of my invention, I wish it to be understood that I do not conline myself tothe precise ldetails of construction herein. set forth. by` way of illustration, as it is apparent that many changes and variations may be made therein, by those skilled Ain the art, Without departing This construction I have 115 from the spirit of the invention, or exceeding the scope of the appended claims.

The motor driven vehicle shown in the drawings and hereinbefore described has an extended traction surface, i. e. the track belts may be of considerable length, the driving wheels and the guide or steering wheels being raised above the ground while the weight of the vehicle is sustained entirely by supportswhich rest on the lower runs of the belts between the driving and guiding wheels. These supports vare .so mounted that they are moved laterally with the beltsl when the latter are bent laterally for steering purposes and they also swing about horizontal axes while being moved laterally. Preferably these supports are in the form of bogies, each carrying a pair of wheels and'springs are interposed at suitable placesin Vthe supports or between the supports and the vehicle frame or body to absorb the shocks.

I claim:

1. A track-laying lvehiclev comprising a pair of iexible tracks upon which the ve hicle travels, means on the vehicle to simultaneously warp the tracks in the same direction, and means to brake one of the tracks to cause the vehicle to turn.

Q. A track-laying vehicle comprising a pair of flexible 'tracksupon which the vehicle travels, a steering mechanism whereby the tracks may be warped, and means attached to the steering mechanism whereby one of the tracks may be braked simultaneously with the warping of the tracks.

3. A track-laying vehicle comprising a pair of iexible tracks upon which the vehicle travels, a steering column, means con nected with the steering column to warp the tracks and means connected with the first mentioned means whereby one of the tracks may be braked simultaneously with, the warpingr of the tracks.

el. A track-laying vehicle comprisinga pair of flexible tracks upon which the vehicle travels, a steering column, a shaft, means operated by the steering column. to rotate the shaft, brake rods, means connecting the brake rods to the shaft whereby only one of the tracks will be braked at one time, and warping mechanism for the tracks connected to said shaft.

A track-laying vehicle comprising a pair of fiexible tracks upon which the vehicle travels, a steering column, a. shaft, gearing operated by the steering columnto rotate the shaft. a steering rod, a link adapted to reciprocate the steering rod when the shaft is rotated. guide wheels running in said tracks. means for turning the wheels connected to said steering rod, brake rods, and means connecting the brake rods to the shaft whereby only one of the tracks will be braked at one time.

6. A track-laying vehicle comprising a pair of flexible tracks upon which the vehicle travels, means for propelling the tracks, guide wheels traveling in the tracks, a steering column, a shaft, gearing operated by the steering column to rotate the shaft. a steering rod, a link connected to the shaft and adapted to reciprocate the steering` rod when theA shaft is rotated, means for turning the guide wheels connected to the steering rod, a gear on the shaft, a brake-lever, a gear on the brakelever meshing with the gear on the shaft, brake rods connected to the brake-lever whereby when the steering wheels are turned the tracks are warped and one. of the tracks is braked.

7. In a motor driven vehicle a frame, endless tractor belts, driving wheels supported by the frame and engaging the belts, guide or steering wheels supported by the frame and also engaging the belts and frame supporting members bearing on the lower runs of the belts between the driving and guide wheels which are mounted to move laterally with the belts whenever the latter are bent laterally for steering purposes.

8. In a motor driven vehicle a frame, endless tractor belts, driving wheels supported by the frame and engaging the belts, guide or steering wheels supported by the frame and also engaging the belts, a plurality of frame supporting members bearing on the lower run of each belt between the driving and guide wheels, and which are independently mounted to move laterally to different extents with the associated belt whenever the latter is bent laterally for steering purposes.

9. ln a motor driven vehicle a frame, endless tractor belts, a pair of driving wheels cooperating therewith, a pair of guide or steering wheels engaging the belts, frame supporting members on opposite sides of the vehicle bearing on the lower runs of the belts between the driving and guide Wheels and which are mounted to move laterally with the belts whenever the latter are bent laterally for steering purposes and springs associated with the supporting members for returning them to normal position when the track belts are straightened.

10. In a motor driven vehicle a frame, endless tractor belts, driving wheels associated therewith, guide or steering wheels also associated with the belts, frame supporting members bearing on the lower runs of the belts between the driving and guide wheels` and which are pivotally mounted to swing fore and aft about horizontal'axes and whichare movable laterally with the belts whenever the latter are bent later-all)v for steering purposes.

ll. In a. motor driven vehicle a frame, endless tractor belts, driving wheels assothe driving and guiding wheels and which are mounted to move laterally'with the belts' whenever the latter are bent laterally for steering purposes.

12. ln a mot-or driven vehicle, a frame, endless tractor belts, driving wheels associated therewith, guide or steering wheels also associated kwith the belts, frame supporting members consisting of wheeled bogies on opposite sides of the vehicle bearing on the lower runs of the belts between the driving and guide wheels and which are mounted to -move laterally with the belts whenever the latter are bent for steering purposes and springs for returning the bogies to normal position.

13. A track laying vehicle comprising a frame, endless flexible tracks carried thereby, frame supporting members bearing on the lower run ot' each track and each mounted to move independently of the others laterally in unison with a corresponding lateral movement of the portion of the track which it engages.

14. A track laying vehicle comprising a frame, a pair of endless flexible tracks, wheels over which the tracks pass and which are raised above the horizontal lower runs of the tracks. means for shifting the front or steering wheels to steer the vehicle by warping or bending the tracks laterally,

frame supporting members bearing on the.

lower runs of the tracks and which are mounted to move laterally with the tracks whenever the latter' are bent laterally for steering purposes.

15.` A track laying vehicle comprising a frame, a pair of endless flexible tracks,4

wheels over which the tracks pass and which are raised above the horizontal lower runs ot' the tracks, means for shifting the front or steering wheels to steer the vehicle by warping or bending the tracks laterally, a plurality of independently .movable frame supporting members bearing on the lowe' run of each track and which are mounte to move laterally with the track whenever the latter is bent laterally for steering purposes. v

16. A track laying vehicle comprising a frame, a lpair of endless flexible' tracks, wheels over which the tracks pass and which are raised above the horizontal lower runs of the tracks, means for shifting the front or steering wheels to steer the vehicle by warp ing or bending the tracks laterally, a plurality of'independently movable frame supporting members bearing on the lower run of each track which are mounted to swing fore and aft of the vehicle and which are moved laterally with the tracks whenever tlie latter lare bent laterally for steering purposes.

17. A track laying vehicle comprising -a pair of flexible demountable tracks, guide wheels on the vehicle adapted to run in the tracks, means whereby the guide wheels may be turned to a limited angle to steer the vehicle by warping or bendinglthe tracks laterally or through a greater'angle when the tracks are moved to 'steer the vehicle by the enga-gement or' the wheels with the road,

`and frame supporting members bearing on the lower lruns of the belts between the driving and guiding `wheels and which are moved laterally. with the belts when the latter are bent laterally for steering 'purposes. In testimony whereof I affix my signature.

LEWIS K. DAVIS. 

